Device employing electronic tubes



Dec. 28, 1937. K E 2,103,621

DEVICE EMPLCYINC ELECTRONIC TUBES Filed June 24, 1953 Jnvenfo r:

l i considerably affected, and it may even occur, contradistinction to the formula, not zero owing l0 7 sirableror necessary Naturally this low Voltage is able toproduce 20 Particularly important is the invention for Sm all anode-Curr only; 20

apparatus which are intended for connection with In der o obtam Sumclent efiects 1t 15 therediff t kinds f current and potentials fore necessary to use Valves of a high amplification Patented Dec. 28, 1937 V t l I 1 2,103,621

UNITED, STATES PATENT OFFICE DEVICE EMPLOYING ELECTRONIC TUBES @Paul Kapteyn, Berlin, Germany, assignor to Radioaktiengesellschaft D. S. Loewe, Berlin- Steglitz, Germany, a company of Germany Application June 24, 1933, Serial No. 677,525 In Germany June 24, 1932 1 Claim. (01. 179-171) For operation of devices operating with elecpossible to solve the problem; nevertheless there tronic tubes, more particularly receiving devices, exists a solution in the case that the magnitude and constancy of the operating po- E tentials is of more or less great importance in the E,,= 5 different stages of the arrangement. Of large in- 5 fiuence, for example, is the magnitude of the that the grid bias is q a pp at anode potential in those stages of the device from equal to the quotient o the anode p t a to which a, regenerative energy is taken, as by a the amplification factor Of the valve. At this decrease of the anode current the back-coupling point of the Characteristic the Current aisrin that the working condition is no longer such as to the fact that besides the voltages to maintain the oscillations. E

The invention has for its object to eliminate dis- E, and

turbances of this nature caused by undesirable 1.; Variations in the anode current and Se f rth there is athird voltage effective, namely the startmeans the an fle current even upon lllg 0f the electrons i. e. the p0t8n= Variations in the operating potentials, may be tial at which the anode potential begins to flow maintained constant i f as this may be which is lndependent of the anode-potential.

According to the invention it is for instance factor (30 or more? f P Y high anflde possible to build receivers which may be com sistances. Under this condltion the effect1ve'connected as desired with a direct-current or an trol Voltage dependsto only a Very Small degree alternating-current supply of any used potential upon the anode Voltage the Valve ltselfi and (100-200 volts) whereby only the series resistance Very low neganve gnd was (at the ordmary Of-the heating circuit has to be changed 7 supply voltages less than 2,5 volts, preferably 0,5

. volts) has to be used. According to the invention the grid b1as for Grid currents may be avoided by using valves 0 the anode current of Whlcl} has to remgfun producing such currents at a positive or very Cons p may be taken m reslstances, Whlch low negative grid potential only; valves in which are directly connected to the anodefcurrentthe support of the emissive cathode material is source, or are traversed by the anode-current of made f tungsten have the desired property the final Stage, in Which the Current is In any case caution has to be taken that in r 3') Varying approximately in D Opottion t0 the P the case of the most positive grid bias occurring 0 tentiel the S pp y- In the tages to be adjusted detrimental grid current is just precluded, whilst consequently the anode potential and the grid even in the case of the most negative grid bias bias are varying practically proportional to the occurring a grating noise (as sometimes produced 40 potential of the supply. by the back-coupling) does not take place. 40

Now, according to the invention, the problem A circuit diagram for a form of embodiment of has to be solved to keep the anode current conthe invention is illustrated in the drawing. This stant under these circumstances. embodiment shows a two valve Wireless receiver When 1 for immediate connection with an A. C. supply J a is the anode-current operated without a transformer. The tubes l and 45 Eg is the grid-bias potential 7 l4 and the rectifier tube 20 possess indirectly Ea is the anode potential of the valve heated cathodes. The filaments 2, I5 and 2| are m is the amplification factor of the valve connected in series with 2. preferably adjustable K is a constant, series resistance H! with the A. C. mains ter- 50 there exists, as Well known, the equation: minals Z y The grid circuit 6, 7 is connected with the grid 5 4 of the first tube and coupled with the aerial cirm cuit l0 and the back-coupling circuit 8, 9. I I is the anode resistance of the first tube, I2 the cou- 5 According to this formula it seems to be impling condenser between the two tubes, and IS the grid leak resistance of the second tube. anode circuit there is situated the resistance filter 33, 34', 35, which is connected on the one hand with the cathode 22 of the rectifier tube and on the other hand with the anodes l8 and 5 of the two tubes l4 and I by means of the loudspeaker 36, or the filter resistance 32 and anode resistance I l.

The cathodes 3 and I6 of the two tubes are connected with each other and in A. C. fashion by filter combinations 26, 21, 28, 29, 30, with the one side of the supply, whereby the resistances 26, 21 serve for producing the grid biases.

I claim:

An arrangement comprising a plurality of electron valves with anode, grid, and cathode, an input circuit, an output circuit, an anode current source, and means for coupling said valves with each other, the first of said valves having a In the high amplification factor of more than 30, the grid of said first valve connected over said input circuit with a resistance capacity combination for effecting a negative potential on this grid relative to the cathode of this valve, said resistance-capacity combination included in the anode circuit of the final power amplifier valve on the cathode side for producing a voltage drop forming said negative potential of the grid of said first valve equal to the quotient of the potential of said anode-currentsouroe and the amplification factor of said first valve, said resistance capacity consisting of a resistance connected through a second resistance to the negative pole of the supply, a condenser being connected in parallel to said two resistances, the input circuit of said first valve connected to the connection point of said resistances.

PAUL KAPTEYN. 

